4,4&#39;-tricarbocyanine salts and their preparation



Patented July 11, 1939 UNITJELDSTATES 4,4'-TRICARBOCYANINE SALTS AND THEIR PREPARATION Leslie G.-S.Br,o0ker, Rochester, N. Y.,.assignor, by

mesne assignments, to Eastman Kodak Company, Rochester, N. Y., a corporation of New Jersey No Drawing. Original application January 16, Y 1933, Serial No. 651,870. Divided and this application August 23, 1934, Serial No. 741,145

a 1 8'Clairns. .(01. 260-240) In this reaction, any condensation product of This invention relates to tricarbocyanine salts and more particularly to. -4,4-tricarbocyanine salts and a'method for their preparation.

This application isa'division of mycopending :3 application Serial No. 651,870, filed January 16,

1933. In this copending application, a preparation of tricarbocyanine salts, wherein a strong organic base is employed as a condensing agent, is described. The 4-, l-tricarbocyanine salts, de- 1 scribed herein-are useful as photographic sensitizers in theinfra-red as described in my copending application, Serial No. 652,029, filed January 16,1933.

It is an object-of the present invention therefore to provide 4,4-tricarbocyanine salts. A

further object is to provide such 4,4' tricarbocyanine salts as are valuable as photographic sensitizers. A still further object is to provide a method of preparing such salts. Other objects 5;; will appear hereinafter.

The 4,4'-tricarbocyanine salts are prepared by condensing two molecular proportions of a lepidine salt which has the following structure:

other suitable anion, with one molecular proportion of a dianilide of glutaconic aldehyde, in the bl presence of a strong organic base.

The reaction can be represented as follows:

@NH: 1101 RX a primary aromatic amine andglutaconic aldehyde will suffice for the dye condensation. Such compounds are referred to hereinafter as dianilides .in accordance with the nomenclature-1 used by Zincke, Ann. 333, .314 (1904).

. A similar method for. the preparation of 2,2- tricarbocyanin'e salts has been. described in British Patent 354,826. However, I have found that this method cannot be applied .to ,the preparation of a,4-tricarbocyanine salts unless 'a strong organic base is employed. Some of the strong organic bases. which 'I have found may be used are n-butylamine, diethylamine, triethylamine, tri-' n-butylamine, piperidine, N-methylpiperidine, triethanolamine, and ,B-diethylamino ethyl alcohol; these'bases have a dissociation constantsubstantially greater than the dissociation constant of pyridine. .Piperidine or triethylamine is preferable. The usual basic condensing agents such as sodium ethyla-te, are incapable-of effecting the condensation.

Further, I have found that carrying .out the condensation at room temperatures or lower is a "decidedly superior procedure to the usual procedure of boiling in alcoholic solution, much '-higher yields being obtained at the lower temperatures.

Examples of typical tricarbocyanine. salts and their preparation will noW be presented.

Example 1.-1,1 '-diethyl-4,4-tricarbocyanine iodide 12 parts (2 mols.) of lepidine ethiodide were dissolvedin 25 parts of hot absolute ethyl alcohol and the solution chilled in a freezing mixture with stirring, so as to obtain very small crystals of the quaternary salt. 5.6 parts (1 mol.) of glutaconic aldehyde dianilide hydrochloride were then added, the mixture stirred, and then 3.4 parts (2 mols.) of piperidine added, with cooling and shaking. A dark coloration rapidly developed and the whole was stood aside in the icebox overnight. Next morning the muddy liquors Were filtered ofi, the residue Washed with acetone until most of the tarry impurities had disappeared, followed by Water and then more acetone. The residue was next boiled with a small quantity of methyl alcohol, cooled and filtered, and this treatment repeated once or twice, until the filtrate was a clear green color and the dye on the filter looked clean. It then consisted of coppery crystals and gave a somewhat dull green solution. The dye could be successfully recrystallized from methyl alcohol, especially if the hot liquors were chilled so as to expose the dye to the action of the hot alcohol for as short a time as possible.

EirctmpZe 2.-1,1'- dimethyZ-4,4'- tricarbocyanine iodide 11.4 parts (2 mole.) 'of lepidine methiodide were treated as in Example 1. The dye obtained was recrystallized from methyl alcohol and obtained as a dark brown powder. The color of the methyl alcohol solution was olive green.

wherein R represents an alkyl group and X represents an acid radical.

2. A tricarbocyanine iodide of the following structure: r

lepidine with one molecular proportion of a dianilide of glutaconic aldehyde.

10. A process for the preparation of a tricarbocyanine salt which comprises condensing, in the presence of a trialkylamine, two molecular proportions of an alkyl quaternary salt of lepidine with one molecular proportion of glutaconic aldehyde dianilide hydrochloride.

11. A process for the preparation of a tricarbocyanine iodide which comprises condensing, in the presence of a strong organic base, two molecular proportions of an alkiodide of lepidine with one molecular proportion of glutaconic aldehyde dianilide hydrochloride.

12. A process for the preparation of a tricarbocyanine iodide which comprises condensing, in the presence of piperidine, two molecular proportions of an alkiodide of lepidine with one molecular proportion of glutaconic aldehyde dianilide hydrochloride.

13. A process for the preparation of a tricarbocyanine iodide which comprises condensing, in the presence of triethylamine, two molecular proportions of an alkiodide of lepidine with one molecular proportion of glutaconic aldehyde dianilide hydrochloride.

14. A process for the preparation of a tricarbocyanine iodide which comprises condensing, in the presence of piperidine, two molecular proportions of the ethiodide of lepidine with one molecular proportion of glutaconic aldehyde dianilide hydrochloride.

15. A process for the preparation of a tricarbocyanine iodide which comprises condensing, in the presence of triethylamine, two molecular proportions of the ethiodide of lepidine with one molecular proportion of glutaconic aldehyde dianilide hydrochloride.

16. A process for the preparation of a tricarbocyanine iodide which comprises condensing in the presence of piperidine, two molecular proportions of the methiodide of lepidine with one molecular proportion of glutaconic aldehyde dianilide hydrochloride.

17. A process for the preparation of a tricarbocyanine salt which comprises condensing, in

R Q Q/ R-N C=CHCH=CHCH=CH-CH=CH-C N wherein R represents an alkyl group. the presence of an organic base having a dissoci- A 1,1-dialkyl4,4='-tricarbocyanine salt.

. A 1,1'-dialkyl-4=,4-tricarbocyanine iodide.

. 1,1-diethyl-4,4-tricarbocyanine iodide.

. 1,1-dimethyl-4,4-tricarbocyanine iodide.

. 1,1-diallyl-4=,4'-tricarbocyanine iodide.

A process for the preparation of a tricarbocyanine salt which comprises condensing, in the presence of a strong organic base, two molecular proportions of an alkyl quaternary salt of a lepidine with one molecular proportion of glutaconic aldehyde dianilide hydrochloride.

9. A process for the preparation of a tricarbocyanine salt which comprises condensing, in the presence of a strong organic base, two molecular proportions of an alkyl quaternary salt of ation constant substantially greater than that of pyridine, two molecular proportions. of a quaternary salt of lepidine with one molecular proportion of a glutaconic aldehyde dianilide hydrohalide. r

18. A process for the preparation of a tricarbocyanine salt which comprises condensing, in the presence of an organic base having a dissociation constant substantially greater than that of pyridine, two molecular proportions of an alkyl quaternary salt of lepidine with one molecular proportion of glutaconic aldehyde dianilide hydrohalide.

LESLIE G. S. BROOKER. 

